Invalid form submission in wordpress

I have a wordpress based classifieds site, i am trying to create and xml feed application that fetches xml from other sites and create ads. I am able to create post in wordpress from the feeds. But i cant copy the images from the remote server,there are no permission issues, i am using the worpress function wp_handle_upload_error, But i get error

This the code

   public function xml_image_upload($upload)
    {
        if ($this->xml_file_is_image($upload['tmp_name'])) 
            {
                $file = wp_handle_upload($upload, $overrides);
            }
    return $file;
    } 

The error i get is “Invalid form submission“

I am trying to solve this for a long time. I cant figure out whats wrong..